The Islamic State group claimed Monday that the shooting massacre in Las Vegas was carried out by one of its “soldiers” who had “converted to Islam” months ago.

“The executor of the Las Vegas attack is a soldier of the Islamic State and he carried out the operation as a response” to calls to target countries engaged in military action against the jihadists, IS’s propaganda outlet Amaq said in online statements.

“The author of the Las Vegas attack converted to Islam a few months ago,” Amaq said, in the statements posted on the Telegram online messaging service.

It provided no evidence to back up its claims.

Fifty people were killed and hundreds wounded on Sunday night when an attacker opened fire on a country music concert in Las Vegas, in the deadliest mass shooting in US history.

Police said Nevada resident Stephen Paddock had been found dead by specialforces responding to reports of gunfire from the 32nd floor of the Mandalay Bay hotel-casino.

At least eight rifles rented by the 64-year-old were found inside the room, he added.

The statements come after IS on Friday released an audio recording of what it said was its leader Abu Bakr al-Baghdadi calling on jihadists in Syria and Iraq to “resist” their enemies.

That was seen as a move to boost the morale of its fighters under pressure in the Syria and Iraq in the face of offensives by the Damascus regime and its allies including Russia and US-backed fighters in both countries.

Since Baghdadi’s previous message to his followers last November, the territory the jihadists still hold in the cross-border “caliphate” they proclaimed in 2014 has shrunk to a fraction of its former extent. (AFP)